Sessa, Emily Butler , Givnish, Thomas J. , Zimmer, Elizabeth .
Relationships of North American Dryopteris based on plastid and nuclear sequences.
Relationships among the thirteen species of Dryopteris (Dryopteridaceae) native to North America have long been subject to speculation among pteridologists. These taxa hybridize readily, forming numerous sterile and several fertile, allopolyploid hybrids. Previous studies of the group have relied solely on morphology and cytology to assess relationships among allopolyploids and their putative diploid parents. The pinnacle of this work was a reticulogram presented by Montgomery and Wagner (1993) in the Flora of North America, depicting putative relationships among the five diploid, seven tetraploid, and one hexaploid species of Dryopteris found in North America north of Mexico. The current study attempts to test this classic hypothesis using molecular data. We sequenced 10 maternally inherited chloroplast genes and rapidly evolving spacers (rbcL, rbcL-accD, trnG, rpl16, matK, pspA-trnH, trnP-petG, trnV-trnM, rps4-trnS, trnL-F) and two biparentally inherited, rapidly evolving nuclear regions (gapCp, LFY) for over 70 accessions, representing all 13 species. Preliminary results indicate support for several aspects of the classic reticulation hypothesis for the group. We plan to use the complete data set to examine biogeographic patterns of species distribution and test for adaptive differences in physiology among taxa found in different light and water regimes.
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1 - University of Wisconsin-Madison, Department of Botany, 430 Lincoln Drive, Birge Hall, Madison, WI, 53706, USA
2 - Smithsonian Institution Museum Support Center, NMNH Department of Botany and LAB, 4210 Silver Hill Road, Suitland, MD, 20746, USA
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Alpine B/Snowbird Center
Date: Monday, July 27th, 2009
Time: 9:15 AM